1. Field of the Invention
The present invention pertains to the art of induction cooking appliances and, more particularly, to an induction cook top appliance with a heat management system.
2. Discussion of the Related Art
Induction cooking, though long a favorite method of cooking in other parts of the world, has only recently become popular in the United States due to its high energy efficiency. Further, induction cooking is more efficient than gas or radiant heat because the cooking elements, i.e., electromagnetic coils, or hobs, are powered by induction generators that induce high levels of current in a pot placed on the cook top, thus heating the pot because of its high electrical resistance. The food or liquid in the pot is heated more quickly because very little heat is lost around the sides of the pot, i.e., the vast majority of heat is transferred directly to the contents of the pot.
During induction cooking the heated pot may radiate heat down into the chassis or housing of the cook top, which can be of the drop in or slide in design as well as free standing. Often times, some type of internal ventilation system is used to evacuate the air in the chassis either upwards through venting slots above the cook top or counter or downward into the cabinet.
Typically, the internal components in the main housing are cooled by moving the heated air out of the housing. However, existing cooling systems do not account for the temperature of the incoming air, i.e., the systems are directed towards air removal from the inside the housing without considering the surrounding air temperature. Further, many existing systems re-circulate the previously expelled heated air back into the housing cavity, thereby increasing the temperature inside. This may result in elevated temperature levels in the housing that may cause component failure and/or reduced cooking performance.
The prior art primarily is directed to controlling the operation of an internal electric fan for cooling the induction heating cooking apparatus, but it fails to address the flow of ambient air outside the housing.
For example, U.S. Pat. No. 4,549,052 discloses an internal cooling system for an induction cooking cartridge. This system includes an internal fan for cooling the various induction heating components. The cooking cartridge features an airflow that enters a mounting recess in at least two areas and enters at both the top and bottom of the cartridge cavity. The airflow is directed over the induction heating circuitry for cooling and is exhausted through the fan to an exhaust conduit. However, this system does not address the issue of the surrounding air intake and the temperature or quality of the air that is brought back into the housing for cooling.
U.S. Pat. No. 4,191,875 is directed toward controlling an internal electric fan for cooling an induction heating apparatus. A thermistor is located near the induction heating apparatus and controls the operations of a fan. The thermistor is in series with a variable resistor and a capacitor. When the capacitor is charged to a predetermined voltage through the thermistor and variable resistor it will fire a signal through a component to allow current to flow through an electronic component and operate the fan motor. This system also includes a plurality of air inlets and outlet holes in the walls of the housing so that the fan randomly pulls air in one side and exhausts out the other side of the housing after passing over the induction heating apparatus. However, this system relies upon the critical factor that the airflow must be undisturbed in cooling.
U.S. Pat. No. 4,415,788 describes an induction cartridge having an internal forced air cooling system where a fan draws air into the cartridge cavity, circulates it around the induction heating components and exhausts it out an opening in the bottom of the cartridge. This patent discloses exhausted air being returned to the kitchen environment through an exhaust gap around the periphery of the cartridge between the housing top and the bottom of a support flange. It is also stated that to protect the air stream that a separate drop in cartridge be made that isolates the induction elements from any other source of blockage.
In another example, U.S. Pat. No. 4,431,892 discloses an induction cook top as a cartridge being fitted into a recess in a housing. The main innovation is an attempt to ventilate the interior of the cartridge using a ventilation system housed in the main body. The cartridge has openings on the side and top for air to pass through once connected to the holes in the down draft ventilator. However, this design is flawed because air that is drawn in will take the path of least resistance, i.e., the air would not be drawn effectively from the cartridge. Without proper air flow, the generator in the induction cartridge would overheat which may result in component failure or destruction.
In U.S. Pat. No. 4,415,788, an induction hob cartridge contains a fan integrated into the hob assembly for cooling the electronics. The problem with this design is that the cartridge does not take into account the exhausted air or the air that is brought into the system. Specifically, the heated air is exhausted out the top edges and may be drawn back into the unit.
In U.S. Pat. No. 4,100,964, an induction ventilation system featuring a liquid cooling system for removal of heat is disclosed. This system can be large, complex and takes up large amounts of space. Moreover, this system does not treat the incoming air. Thus the exhausted heated air may be returned back into the cavity of the housing.
In U.S. Pat. No. 4,549,052, an induction hob cartridge contains a fan integrated into the hob assembly for cooling the circuitry. This design does not take into account where the air is exhausted and the potential of drawing the exhausted air back into the cavity. Specifically, the heated air is exhausted out the top edges and may be drawn back into the unit if the exhausted air is not moved away from the intake vents for the cartridge.
Therefore, there exists a need for a state of the art indoor or outdoor induction cook top with heat management system to control the heat generated by the components, electronic controller, mechanical controls, or the induction generators, providing precise temperature control and efficient heat removal without drawing exhausted air back into the system. Further, there exists a need for an induction cook top having a smaller depth for ease of extraction and no venting above the counter. There exists a need for the user to be able to view/see the operation, functions, and view the codes on the cook top. There also is needed a new cook top construction such that it can be used in limited spaces and places. Finally, there is also a need for a proper vent design so as to efficiently remove undesired heated air from the housing of an induction cook top appliance.